Abstract: Various mixtures of synthetic apatite, magnesium oxide and silica oxide in various proportions have been fused at 1400℃, for thirty minutes. The citric acid solubility of the products has been determined. At SiO2/MgO ratios of 1 to 2.6 by weight, the percentage of synthetic apatite in the mixtures corresponding to the highest citric acid solubility of the products, has been found to be within the range of 40% to 46%. It has been found that, if the SiO2/MgO ratio in the mixtures is greater than 3, the citric acid solubility of the products decreases suddenly. If the R2O3 content in the mixtures is not too high, for example, 5% R2O3, the citric acid solubility of the product is slightly higher than that in the absence of R2O3.

摘要： <正>近代各国制造熔融含镁磷肥,主要是用含氧化镁和二氧化硅较高的蛇纹石或橄榄石同磷矿石进行配料,在高温条件（大约在1350—1400℃以上的温度）下熔融一定时间,熔融品出炉以後被骤然冷却,而得成品磷肥,其中含有效的五氧化二磷较高。如果用白云石